Seals practise social distancing, aerial survey of North Sea shows
对北海的航空调查显示，海豹也保持社交距离
Research suggests behaviour may reflect evolutionary response to previous outbreaks of disease
研究表明，该行为可能反映出海豹对此前疾病爆发的进化响应
Aerial surveys of the North Sea have revealed that seals practise social distancing – and the discovery may have profound implications for the spread of disease among the marine mammals.
北海的航空调查揭示海豹保持社交距离，这一发现可能对海洋哺乳动物间疾病传播产生深远影响。
In a paper published today by the Royal Society, researchers conducting censuses of grey and harbour seals detail new evidence that the two species not only maintain distances between their own kind (unlike walruses, for instance, who cluster close together) but also that this behaviour may “reflect an evolutionary response to viral susceptibility”.
在英国皇家学会今天发表的论文中，研究人员在对灰海豹和港海豹进行普查后，详细说明了两个物种不仅在自己的种类之间保持距离（这与海象等紧密群聚的物种不同），而且这种行为可能“反映了对病毒易感性的进化响应”。
“By comparing harbour seal colonies with grey seal colonies, we have found that harbour seals keep a greater distance from their neighbours than grey seals do,” the report’s lead author, Jeroen Hoekendijk, told the Guardian.
报告第一作者耶罗恩·胡肯迪克告诉《卫报》：“通过将港海豹群与灰海豹群进行比较，我们发现与灰海豹相比，港海豹彼此之间会保持更大的距离。”
The area surveyed was a wild expanse on the coast of the Dutch Wadden Sea, where both species of seals “haul out” on the intertidal flats and beaches to rest, socialise, mate and give birth. They gather there in great numbers. Up to 6,500 grey seals choose the high sandbanks, while harbour seals – about 8,000 were observed – prefer sands revealed at low tide.
航空调查的区域是荷兰瓦登海的海岸线野生地带，在那里两种海豹“上岸”潮间带和海滩，以休息、社交、交配和分娩。它们在那里聚集成群，高沙堤上有多达6500头灰海豹，而港海豹（约8000头）则更喜欢在低潮时露出的沙滩上。
Unfortunately, the large numbers of harbour seals have faced disastrous outbreaks of disease in the past. Phocine (seal) distemper virus ravaged the populations in 1988 and 2002, halving numbers. About 18,000 harbour seals died of distemper in the UK and Europe in the 1988 outbreak . Grey seals, however, remained relatively unharmed.
不幸的是，大量港海豹曾遭遇灾难性的疾病爆发。海豹瘟热病毒在1988年和2002年肆虐，导致港海豹数量减半。1988年的瘟疫爆发导致约18000头港口海豹在英国和欧洲死亡。然而，相较之下灰海豹没有受到太大影响。
“Many grey seals were actually also infected, but just didn’t get as sick as harbour seals,” said Hoekendijk. “This may actually have contributed to the spread of the virus. They carry the virus, but can still move around freely.” He pointed to recent evidence that the grey’s reduced susceptibility had “genetic underpinnings”.
胡肯迪克说：“事实上，很多灰海豹也被感染了，但它们没有像港海豹那样严重。这其实可能导致病毒的传播，因为它们携带病毒，但仍然可以自由移动。”他指出，根据最近的证据，灰色海豹的较低易感性具有“基因基础”。
Fascinatingly, it may be that the social distancing described in the new report represents a memory of those severe outbreaks. “Other studies have shown that grey seals are more resistant to respiratory viruses than harbour seals,” said Hoekendijk. “The greater inter-animal distances that we’ve observed for harbour seals in our study might be a response … very similar to our response during the Covid pandemic.”
有趣的是，新报告中描述的社交距离可能代表了对那些严重疫情爆发的记忆。胡肯迪克说：“其他研究已经显示，与港海豹相比，灰海豹更能抵抗呼吸道病毒。我们在研究中观察到的港海豹之间更大的动物距离可能是一种响应，这与我们在新冠疫情期间的响应非常相似。”
It is not a bad idea for humans to keep their distance from seals, too. Not only is there a danger of being bitten, the bites have been linked to potential human-animal zoonosis in the form of the notorious “seal finger” caused by contact with seals’ claws or teeth. If the skin is broken, infection has led to the amputation of human digits among fishers and scientists.
对人类来说，与海豹保持距离也无妨。接触海豹不仅存在被咬伤的危险，这些咬伤还与潜在的人畜共患病有关，如果海豹的爪子或牙齿接触，会出现“海豹手指”症状。如果皮肤破损，感染可能导致渔民和科学家的手指被截肢。
